String Breakage

[Roger Jolly]

Hi Tony,
        Since the torque of the pins is so low, as not to hold, are you
raising the string more than normal, the wire is being worked hardened with
the back and forth movement. In a normal situation the drop in pitch is
caused be other factors, not the pin slipping. Time the pins are loose,
could it be that the piano wire has also reached the end of it's usefull
life? How much and how fast is the drop in pitch? How frequently are you
having to retune? This should give a clue if the meer act of tuning is work
hardening the wire at a faster rate. For instance, if you are raising some
notes 1/2 a semi tone every couple of months, it will not take long to give
this kind of problem.

If the piano was in my charge, I would suggest restringing as well as
repinning, Yamaha's repin very well with 2.0 pins in most cases. It's about
1/2 the price of the pins from Japan. If you need to go two sizes over,
then contact Yamaha USA for the right size pins. 

When restringing a concert piano I also insist on new dampers, since taking
this approach I have greater satisfaction from clients. If they can afford
a concert grand, they should be able to afford to have the job done correctly.

Hope this is of some help.
Roger



At 10:43 PM 3/8/99 +0930, you wrote:
>
>Hi List,
>
>String breakage, I never got  all the answers on this subject so I will
ask, why do the strings break at the point where the wire starts curving
around the tuning pin?
>
>I have a CF Yamaha in my care that is now breaking strings in the bass A0,
B1 & G1.  All singles. So far. All T pins are loose.
>
>History.  The piano has been stored in  a 5% humidity environment,  the
tuning pins are loose some very loose, and over the last 5 years the piano
is constantly out of tune with pins slipping.  Constant spasmodic tuning,
>
>The owners wants to know what is the cause of the breaking strings ?  What
is the cause ?
>
>I have read most of what was said on this subject but I can't recall if an
answer was given.
>
>Please help me give the right information to the owners.
>
>To me, I am querying the clues given in this thread and am offering and
asking for assistance in either proving or disproving the following theory.
>
>Because when piano wire is down down to the required dimension, the outer
part of the wire goes hard while the inner core remains softer.
>
>1.     Is this process work hardening the wire in a controlled process and
then other excessive bending causing the outer side hard wire to crack.  ???
>
>2.    Should piano wire because of the hard outer and soft core be more
likened to a metal tube filled with lead.
>What would happen if you flex or bend the tube back and forth a few times,
would this cause the metal tube to crack. ?
>
>I am no engineer or metallurgist but this seems feasible to me.  BUT what
do I tell the owners that caused the strings to break.
>
>
>Regards   Tony Caught  caute@accessnt.com.au
>
>
>
>Attachment Converted: "c:\eudora\attach\ReString.htm"
>
Roger Jolly
Balwin Yamaha Piano Centres.
Saskatoon/Regina.
Canada.